从字典列表创建 Pandas DataFrame
Luqman Khan
2022年5月16日
字典是一个紧凑而灵活的 Python 容器，用于存储单独的键值映射。字典用大括号 ({}) 编写，其中包括用逗号 (,) 和 : 分隔每个键与其值的关键字对。
下面显示了三个字典，其中包含一个骰子游戏的示例。
让我们以骰子游戏为例。在这种情况下，两名玩家滚动他们的六个骰子并与相应的玩家存储骰子。
import pandas as pd
from numpy.random import randint
# create datset from multiple dictionaries
dataset_list = [
{"Harry": 1, "Josh": 3, "dices": "first dice"},
{"Harry": 5, "Josh": 1, "dices": "second dice"},
{"Harry": 6, "Josh": 2, "dices": "third dice"},
{"Harry": 2, "Josh": 3, "dices": "fourth dice"},
{"Harry": 6, "Josh": 6, "dices": "fifth dice"},
{"Harry": 4, "Josh": 3, "dices": "sixth dice"},
]
df = pd.DataFrame(dataset_list)
print(df)
print()
harry = []
josh = []
for i in range(6):
harry.append(randint(1, 7))
josh.append(randint(1, 7))
我们从包含字典的项目列表中创建了一个数据集，因为我们知道 DataFrame 采用键值对。这就是为什么这适用于字典。
输出：
Harry Josh dices
0 1 3 first dice
1 5 1 second dice
2 6 2 third dice
3 2 3 fourth dice
4 6 6 fifth dice
5 4 3 sixth dice
我们在上一个例子中手动设置骰子；现在，我们将使用 numpy 库中定义的 randint 方法。我们在下一行创建了两个名为 harry 和 josh 的空白列表。接下来，我们创建了一个 for 循环，该范围定义为 0-6，使用 append() 方法将两个已定义列表中的随机数作为元素附加，如下所示。
import pandas as pd
from numpy.random import randint
print()
harry = []
josh = []
for i in range(6):
harry.append(randint(1, 7))
josh.append(randint(1, 7))
# create datset from multiple dictionaries
dataset_list = [
{"Harry": harry[0], "Josh": josh[0], "dices": "first dice"},
{"Harry": harry[1], "Josh": josh[1], "dices": "second dice"},
{"Harry": harry[2], "Josh": josh[2], "dices": "third dice"},
{"Harry": harry[3], "Josh": josh[3], "dices": "fourth dice"},
{"Harry": harry[4], "Josh": josh[4], "dices": "fifth dice"},
{"Harry": harry[5], "Josh": josh[5], "dices": "sixth dice"},
]
df = pd.DataFrame(dataset_list)
print(df)
请记住，randint() 的范围从给定的 1 到 n-1，或者默认情况下从零到 n-1，这就是我们定义从 1-7 的范围的原因。
输出
Harry Josh dices
0 4 1 first dice
1 4 2 second dice
2 3 4 third dice
3 1 1 fourth dice
4 4 5 fifth dice
5 4 4 sixth dice
现在我们在 for 循环的帮助下减少了代码行，并将整个字典附加到一个列表中，进一步在名为 index 的列表中附加索引与玩家回合相对应并设置为 DataFrame 中的索引。
import pandas as pd
from numpy.random import randint
dataset_list = []
index = []
for i in range(1, 7):
dataset_list.append({"Harry": randint(1, 7), "Josh": randint(1, 7)})
index.append("dice " + str(i))
print("\nAfter reducing the code\n")
df = pd.DataFrame(dataset_list, index=index)
print(df)
输出：
Harry Josh
dice 1 2 4
dice 2 2 3
dice 3 6 5
dice 4 5 2
dice 5 4 2
dice 6 1 1
所有示例：
import pandas as pd
from numpy.random import randint
# create datset from multiple dictionaries
dataset_list = [
{"Harry": 1, "Josh": 3, "dices": "first dice"},
{"Harry": 5, "Josh": 1, "dices": "second dice"},
{"Harry": 6, "Josh": 2, "dices": "third dice"},
{"Harry": 2, "Josh": 3, "dices": "fourth dice"},
{"Harry": 6, "Josh": 6, "dices": "fifth dice"},
{"Harry": 4, "Josh": 3, "dices": "sixth dice"},
]
df = pd.DataFrame(dataset_list)
print(df)
print()
harry = []
josh = []
for i in range(6):
harry.append(randint(1, 7))
josh.append(randint(1, 7))
# create datset from multiple dictionaries
dataset_list = [
{"Harry": harry[0], "Josh": josh[0], "dices": "first dice"},
{"Harry": harry[1], "Josh": josh[1], "dices": "second dice"},
{"Harry": harry[2], "Josh": josh[2], "dices": "third dice"},
{"Harry": harry[3], "Josh": josh[3], "dices": "fourth dice"},
{"Harry": harry[4], "Josh": josh[4], "dices": "fifth dice"},
{"Harry": harry[5], "Josh": josh[5], "dices": "sixth dice"},
]
df = pd.DataFrame(dataset_list)
print(df)
dataset_list = []
index = []
for i in range(1, 7):
dataset_list.append({"Harry": randint(1, 7), "Josh": randint(1, 7)})
index.append("dice " + str(i))
print("\nAfter reducing the code\n")
df = pd.DataFrame(dataset_list, index=index)
print(df)
输出：
Harry Josh dices
0 1 3 first dice
1 5 1 second dice
2 6 2 third dice
3 2 3 fourth dice
4 6 6 fifth dice
5 4 3 sixth dice
Harry Josh dices
0 4 1 first dice
1 4 2 second dice
2 3 4 third dice
3 1 1 fourth dice
4 4 5 fifth dice
5 4 4 sixth dice
After reducing the code
Harry Josh
dice 1 2 4
dice 2 2 3
dice 3 6 5
dice 4 5 2
dice 5 4 2
dice 6 1 1